1. Field of the Invention
The present invention relates to a charging system for minimizing system energy or commercial energy applicable to an electrically driven vehicle having a vehicle-mounted electric storage device, which can be charged from an external electric charger. The electrically driven vehicle includes an electric vehicle (EV), a plug-in hybrid vehicle (PHEV), a plug-in fuel cell vehicle (PFCV), or the like.
In the following description, the term “energy” refers to electric power [W], and the term “amount of energy” refers to an amount of electric power [Wh].
2. Description of the Related Art
Heretofore, there has been proposed a battery charging system, which stores renewable energy such as wind power or solar power, together with system energy (commercial energy) supplied from an electric power company or the like, in a stationary electric storage device that is placed at a residential building or the like. In such a system, an electric vehicle battery is charged at a charging site, e.g., such as a residential building, which is equipped with the stationary electric storage device. For details, reference should be made to Japanese Laid-Open Patent Publication No. 2011-125122.
In the battery control system disclosed in Japanese Laid-Open Patent Publication No. 2011-125122, the total amount of electric power consumption in the residential building is estimated to include an amount of electric power consumption (energy consumption) of the electric vehicle. If the amount of electric power, which is obtained by adding the storage amount of the stationary electric storage device and the amount of solar power generated by a solar panel, it lower than the estimated amount of electric power consumption, the amount of electric power (system energy) to be stored in the stationary electric storage device is purchased from an electric power company, or is generated by a generator using natural gas or hydrogen, so that a necessary amount of electric power is stored constantly in the stationary electric storage device. Japanese Laid-Open Patent Publication No. 2011-125122 describes that it is possible for the system to efficiently control the stationary electric storage device that is introduced into the residential building or the like (see paragraphs [0036], [0047], and [0052] of Japanese Laid-Open Patent Publication No. 2011-125122).